Most marine inboard engines for small boats are marinized versions of automotive engines. Typically, these engines use open cooling systems which take in water from the body of water the boat is in, and circulate that water through a water jacket surrounding the engine to cool the engine. When the boat is not in use, the water is trapped in the cooling system inside of the engine. During winter months the engine water must be drained to prevent it from freezing, expanding and cracking the engine. Additionally, the engine water also causes corrosive damage to the engine when left inside between regular operations. If it were easy to drain the engine, the water could be drained after every use to prevent rust and scale from developing inside the water jacket of the engine.
In any climate where the air temperature falls below the freezing temperature of the lake water, the owner typically drains and winterizes the engine and the boat cannot be used until there is no possibility of freezing weather. This causes an inconvenience to those who would like to use their boat during winter months. An invention that would make it easy for the average consumer to drain their engine would not only make it more convenient for people to use their boat in areas where it gets down to freezing a couple months out of the year, but would also open up the market for this type of boat to colder areas. An additional advantage of easy drainage is compliance with new laws in some states requiring drainage of the engine and other water reservoirs from the boat whenever the boat is moved from one lake to another in an effort to prevent the spread of invasive aquatic species such as zebra mussels.
Several quick drain systems already exist, but none of them have a way of verifying that they have functioned properly and thoroughly. Without a way of verifying that the drain has functioned properly, there is no way of knowing if there is still water left in the engine. This could result in costly repairs and is a liability to the manufacturer of the drainage system and the manufacturer of the engine should they allow this type of system to be mounted to their engines. However, with a way of verifying, the end user and the manufacturer can rest assured that the boat is safe and ready to use year round.
Furthermore, currently the only way to check that the engine cooling system is working properly is the thermometer. If the coolant system is working properly the thermometer will display an engine temperature that is within certain parameters specified by the engine manufacturer, usually in the engine manual. If the coolant system is not working properly, the only way of knowing is when the thermometer reads above normal. However, by the time the thermometer reads above normal the engine is already overheating. To make things worse, by the time the average boat owner notices that the temperature is above normal, the boat is already being operated outside of the boathouse, away from the dock or boat launch, and the driver must either risk further overheating of the engine by driving back or play it safe and turn the engine off and paddle or swim the boat back. The manufacturer designs the engine operating temperatures with a factor of safety to allow for delayed detection of cooling system problems without immediate damage. However, if there was a way of monitoring the engine cooling system, the boat operator would be notified that the engine is not working properly before it over heats and before the boat leaves the boat house or dock. Additionally, this ability for early detection would allow for the engine manufacturer to reduce the factor of safety thus allowing them to further optimize engine performance.
Valves currently available on the market typically are single port valves that control flow through one inlet and one outlet only. There are multiport valves, although most are used to divert flow or mix fluids. There are no available options for draining multiple ports simultaneously while keeping the fluids separate when the valve is closed. The option of using multiple valves that can be actuated individually is viable, however this quickly becomes expensive especially when using electric valves.
When draining multiple sources of fluid, the goal is to pass the fluid through a bulkhead, such as the hull of a boat or the wall of a container. The standard pipe fittings that pass through a bulkhead use NPSM thread (National Pipe Straight Thread for Free-Fitting Mechanical Joints). This thread allows the fitting to be secured to the bulkhead using a lock nut on the backside of the bulkhead, but it provides a difficult joint to attach to since valves use NPT (National Pipe Tapered Thread). In order to drain multiple hoses through one bulkhead fitting, multiple valves would have to attach to a manifold to collect the fluid. Then the manifold would have to attach to the bulkhead fitting through a hose and an adapter fitting or an oversized hose that could fit over the bulkhead fitting and tighten using a hose clamp that would provide an imprecise connection. Another issue confronting automated drainage is the presence of fluid at the output of the valve. If there is fluid at the output of the valve before it opens, then the inlet fluid will not be able to flow through the valve as desired once it is opened. A sensor that could detect fluid at the output would be very beneficial to allow for the output to be cleared before attempting to drain.